Effect of canal blocking on biodiversity of degraded peatlands: Insight from West Kalimantan

PLOS One | https://doi.org/10.1371/journal.pone.0334014 October 8, 2025 4 / 23 Raya landscape (Fig 2). Each site has its own characteristic, which we compile in Table 1. We conducted the field surveys twice, once during the wet season and the other during the dry season. The initial survey was conducted from May 5th to May 26th, 2023, to collect data during the wet season, followed by a dry season survey from August 3rd to August 25th, 2023. Prior to data collection, we obtained approval to conduct the study from the Dean of the Faculty of Forestry, Universitas Gadjah Mada. As the study was conducted across two regencies and involved lands owned by the village and individual community members, we were required to obtain permissions from both provincial and local authorities. We received writ- ten approval from the West Kalimantan Province Office of Investment and Integrated One-Stop Services (DPMPTSP Kali- mantan Barat), as well as verbal permission from the head administrators of each village where the research took place. Survey methods Wildlife attributes. We collected wildlife data by utilizing line-transects to assess mammals and herpetofauna. We established three line transects within every habitat category, resulting in a total of 12 transects (Fig 1). Each transect had a length of 1 km and was positioned perpendicular to the neighboring access road or canal. The starting point of each transect was set at 100 meters from the road or canal to minimize edge effects. Upon sighting a species, we recorded species name, number of individuals, and coordinates.

We used point counts to assess bird diversity. Along the transects, six point-counts were established, each with a circle radius of 50 m, resulting in a total of 72 points. To prevent double counting during observation, there was a 200 m spac- ing between each point count. Each point count was assigned a 10-minute observation window. During the observation period, data including species name and individual count were recorded. Bird positions were documented using the coor- dinates of the point location. Fig 2. Habitat preview with figure. (A) showing estate crop, (B) showing disturbed wet shrub, (C) showing disturbed peat forest, (D) showing less disturbed peat forest. https://doi.org/10.1371/journal.pone.0334014.g002